In this study, we have established a new strategy increasing human islet longevity utilizing allogeneic whole bone marrow (BM) cocultured with human islets. The cultured islets' function and survival have been evaluated by analysis of insulin secretion in response to high-glucose-challenge, morphological evaluation of cell growth. Human islet only culture failed to reveal evidence of long term survival, growth or function in terms of insulin release or insulin response to glucose challenge. These results indicate that BM increases islet survival and function with the eventual formation of pancreatic endocrine tissue capable of sustaining beta cell fuction. (C) 2007 Elsevier Inc. All rights reserved.